Warehousing operations can encompass a large number of different items in storage awaiting shipment to many different possible locations. It is common practice to refer to the same type of item in a warehouse as a "sku" which is an acronym for "stock keeping unit". Thus, as used here, the term "sku" is used to refer to an individual type of item. That is, although there may be many of the same type of item in a warehouse, they will all be kept track of by the same sku designation, since they are all supposed to be "identical" products or goods.
In a typical warehouse operation, items in storage may, for example, be needed for shipment to many customers, shipments to other plants, or shipments to other locations at the same plant but at a different work station. Sometimes an individual shipment might involve only one item for a particular destination, or several of the same item, but more typically, especially in the case of filling orders for a customer, would involve one or more of several different items or sku's going to a particular location. This process would necessarily then be repeated each day on a continuing basis for many different customers and locations. For example, a clothing manufacturer may have many different product lines, and within each line, many different styles, sizes, colors, etc. Any one customer may order several different items from the various product lines, sizes, colors, styles, etc., and this would be true for each of a manufacturer's many customers.
Thus, it should be apparent that the items needed for shipment at any one particular time may be very different from one day to the next, or even from one hour to the next.
The assembly of items for shipment can thus be a complicated matter, especially if it is to be done on a cost effective basis. Manpower requirements, shipping charges, the physical space requirements needed to carry on the operation, capital investment, and the turn-around time needed to complete shipments all need to be kept as low as possible. In order to optimize these factors and their related expenses, various equipment and operating systems have been used. For example, it is known that by consolidating items for shipment to each particular destination, shipping costs can be reduced, as long as the cost of consolidating the items does not exceed the savings. Thus, it is important that a warehouse have a cost effective mechanism to consolidate from the whole inventory of goods, all of the items currently on order for shipment to each of their particular destinations. Various conveyor systems and operating systems have been utilized to automate warehouse operations, but generally involve the need for more space and more capital investment.
Typically in the past, stored items were kept in a particular dedicated location. A particular item or sku was stored in its own location or storage bin on a substantially permanent basis. To fill and order, a worker (called a "picker") was given a "pick slip" or "packing slip" which listed all of the items needed to fill a particular order. In some systems the pick slip is an electronic or other signaling device used to indicate to a picker which items to pick for filling an order.
Depending on the nature of the item(s) being stored, a particular item may be in a bin, or tray, or rack, or simply on a pallet. Whatever type of storage device is used, it is generally referred to as a "pick face". When an item was needed to fill an order, a picker would travel to the particular pick face, possibly with a cart, and manually "pick" the needed number of items from that location, and add the item(s) picked to the particular order being filled. If many different items were needed for shipment to a particular destination, the picker had to travel to the pick face for each of the different items needed. This process was a time consuming process.
Also with regard to the picking areas, and in particular with regard to the configuration and layout of the pick faces, it has always been desirable to minimize, as much as possible, the physical space required for the pick faces and the overall picking area itself so as to reduce the time required for a picker to travel the pick area and reduce the physical plant required to house the picking area, but still allowing enough room between pick faces to conveniently remove items from the pick face.
In order to speed the process today, many warehouses utilize conveyor systems with automatic diverters under automatic computer control. Some systems for example use computers in conjunction with various types of sensors or scanners that keep track of individual items on a conveyor, the location of the item along the conveyor, a prioritized destination of that item, etc. The sensors or scanners are placed at various locations along the conveyor route to automatically read or detect various types of information. In some applications, optical sensors are used, while in other applications, weight sensors, magnetic sensors, or some other appropriate type of sensor is used to detect and/or identify items on the conveyor. In still other systems, scanners are used to read coded machine-readable labels on the items, so as to update and check on the various system parameters, item location, and other data, on a constant basis, and to provide feedback for the purpose of correctly and automatically activating diverters to route packages and other items to their proper destination within the warehouse.
The conveyors have taken various forms. Some have been simple belt or roller conveyors, while others have individual trays for individual items or cartons of items, and are well known to those skilled in the art.
Diverters have been developed into many forms. Some systems have used "push" levers or arms, or pop-up wheels that are operated under solenoid, pneumatic, or other automatic control, to automatically direct individual or multiple items from one conveyor to another, or into chutes, storage bins, etc. Still other systems have devised diverting systems comprised of individual tiltable trays on a continuous conveyor track under computer or other automatic control. This latter type of automatic diverter system, while somewhat new, is now well known in the art.
As noted, the tilt tray type conveyor generally comprises a continuous series of individual trays riding on a conveyor track. Each tray is capable of being tilted at an angle to the direction of travel of the conveyor track, such that when an individual tray is tilted, its contents slides off of the tray (at a predesignated location), again for example, onto a chute or onto another conveyor leading to a storage bin, etc. The operation of the "tilt"-able tray systems is such that the trays are tilted while the conveyor is moving, but the timing of the tilting is selected such that the item on the tray accurately arrives at its intended destination.
In another tray type conveyor, each of the trays has an automatic belt mechanism on its upper surface which can be automatically activated to eject its contents off of the tray at an angle to the direction of the conveyor travel, again, with proper controlled timing, into a chute, bin, etc.
The operation and control of such tilt-tray, or belt diverting tray type conveyors, generally involves complex computer control, but this aspect of the warehousing operation is well known in the art and need not be discussed in detail here. Other conveyor systems and diverter systems are known as well.
But even with the advent of computers, the assembly of orders still involves, on a large basis, the use of human workers assisting, to a greater or lesser degree, the automated system(s) being used. And, other warehouse operations are still by and large manually conducted with the simplest type of belt, wheel, or roller type conveyor, with workers manually transferring items from one conveyor to another, from a conveyor into a storage bin, etc., or possibly without the use of a conveyor at all.